Reaction biodiesel manufacturing

The second area of heterogeneous catalysis in biodiesel manufacturing is the transesterification reaction. Here again, the base catalysts exhibit typically much higher activity than the acidic ones, but finding effective catalysts is still an open problem. Some solid metal oxides, such as those of tin, magnesium, and zinc could be used directly, but they actually act by a homogeneous mechanism... 

A key operation in biodiesel manufacturing is the separation of glycerol and FAM E from the reaction mixture by liquid-liquid decanting. Thermodynamic studies on this subject are scarce despite the industrial interest Table 14.11 presents data for... 

The last two chapters are devoted to problems of actual interest, manufacturing biofuels from renewable raw materials. Chapter 14 deals with Biodiesel Manufacturing. This renewable fuel is a mixture of fatty acid esters that can be obtained from vegetable or animal fats by reaction with light alcohols. A major aspect in... 

Fatty acids react with alkaline catalysts to form catalytically inactive soaps (3). The chemical reaction consumes one mole of fatty acid per mole of alkaline catalyst. Although fatty acid composition of the starting material varies, the content determined by titration reflects the amount of catalyst that would be consumed in a chemical reaction. By calculation, it may be determined that one gram of fatty acid (expressed as oleic acid) will react with about 0.2 g of anhydrous potassium hydroxide or 0.14g of anhydrous sodium hydroxide. Often, additional catalyst must be added to esterify a vegetable oil containing higher levels of fatty acids (3). Conversely, acid catalysts are not inactivated by fatty acids (3). In a unique reaction, fatty acids produced during biodiesel manufacture are actually used as a catalyst in their own esterification (see below). 

Biodiesel production via a membrane reactor has shown great performance because it overcomes the serious issues of conventional reactors. Both production and separation using membrane technology have provided a suitable opportunity for companies to manufacture biodiesel beneficially. However, there are some challenges in using membrane reactors for the production of biodiesel that need to be resolved, such as limitation caused by its material, shape, and pore size (Ned Hall), the high cost of some kind of membranes (Murphy et al., 2010), the slow rate of reaction (Dube et al., 2007), and issues related to the presence of alkaline catalyst with water (Baroutian, Aroua, Raman, Sulaiman, 2010a). 

In summary, with respect to benefits and drawbacks of DMC as an alternative reagent for carrying out interesterification of oil and fats to produce biofuel from renewable resources and alternative co-products (GC and glycerol dicarbonate (GDC)), it should be mentioned that DMC is a less toxic chemical than methanol that can be currently manufactured by environmentally safe industrial methods, from CO2 and renewable resources. Besides, GC and its derivatives are characterized by low toxicity, and the remaining nonreacted DMC does not need to be separated from the reaction products, because it is an effective additive for diesel engines, due to its high oxygen content (Bounce et al., 2010). Here we have that the fabrication process is very simplified with respect to the conventional biodiesel obtained from methanol. 

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